Striping attachment for metallizing spray gun



Nov. 26, 1963 J. MALONE 3,112,072

STRIPING ATTACHMENT FOR METALLIZING SPRAY GUN Filed June 26, 1962 i i J INVEN TOR. JOSEPH MAI-0N5 kwfw United States Patent 3,112,072 STREPENG ATTACEHWENT FGR METALLIZING SPRAY GUN Eoseph Maione, 98 Gordon Ave, San Jose, Calif. Filed June 26, 1962, Ser. No. 265,366 3 Claims. (Cl. Z3 79) The present invention relates to metallizing guns, and pertains more particularly to a pattern restricting attachment for adapting a conventional, diverging spray type metallizing gun for use in striping.

The term metallizing as used herein, and as used generally throughout the industry, means the spraying of heat-fused droplets of metal or other high melting point substance onto a surface to be coated with the particles. A well known type of metallizing gun feeds a metal wire at controlled speed into a oxy-hydrogen or oxy-acetylene flame, and subjects the thus molten metal to a high velocity jetstream of air or gas, which atomizes the molten metal and discharges it in a diverging or fan shaped spray of molten spray droplets. When these molten spray droplets impinge upon a suitable surface toward which the spray is directed, such as clean metal surface, the molten particles bond themselves to such surface and thus provide a dense, substantially integral surface coating of the deposited material thereon.

Where a surface area of substantial length and breadth is to be thus metallized, the ordinary metallizing guns are adequate. However, where only a small portion of such a surface is to be metallized, and the remainder of such surface is to be left free of the surfacing material, or where the metallizing material is required to be applied to a surface in a band or stripe, such operations have been accomplished in the past by masking the margin of such portion with suitable sheet material which will withstand the hot metal spray blast, such as adhesive coated asbestos tape.

When such problems arise in production quantities for example, the application of a metallized strip to several, or even hundreds or thousands of work pieces, the masking, and subsequent stripping oil of the masking material adds labor and material costs sometimes far in excess of that of the actual metallizing operation itself.

The present invention provides a striping attachment for a metallizing gun which restricts the usual divergent spray pattern thereof to a small diameter, substantially cylindrical pattern which can be traversed in a desired path along a surface so as to apply thereon a metallized stripe of a width equal to the diameter of such restricted pattern.

A further object of the invention is to provide a tubular attachment for receiving the diverging molten spray particles emitted by a metallizing gun and directing such particles in a controlled, restricted pattern for depositing on a surface toward which the gun is directed.

A further object of the invention is to provide a striping attachment/fortrmetallizing gun said attachment comprising a tubular barrel portion mounted co-axially of the gun nozzle, and spaced therefrom, the barrel portion having a highly polished bore through which the spray fron /the gun is directed in a controlled and laterally restricted pattern, means being provided for cooling the bairel portion.

A further object of the invention is to provide an improved striping attachment for a metallizing gun.

These, and other objects and advantages of the invention, will be apparent from the following description and the accompanying drawings, wherein:

FIG. 1 is a longitudinal, sectional view of a striping attachment emboding the invention as it appears when mounted on a metallizing spray gun, the nozzle and adjacent portions of the metallizing gun being shown in broken lines, the spray of molten particles emitted from the spray gun being indicated passing through the attachment and impinging upon a surface to be metallized, portions being broken away.

FIG. 2 is a sectional view taken along line 22 of FIG. 1.

Briefly, the illustrated embodiment A of the invention comprises a clamp ring portion 11 for clamping the attachment A to the nozzle 11, shown in broken lines in FiG. 1, of a conventional metallizing gun B, only a portion of which is shown in FIG. 1. A throat portion 12, with air-admitting openings 13 therein, and a tubular water jacket portion 14 are formed integrally with the clamp portion 10. A barrel tube 15 is removably inserted in sealed relation in the water jacket portion 14, in axial alignment with the nozzle 11, and spaced axially therefrom to receive a divergent, high velocity jet stream C of molten spray particles discharge from the metallizing gun nozzle 11. The bore 17 of the barrel tube 15 is of true form and highly polished. Coolant fluid, such as water, is circulated through a water jacket 18 between the portion 14 and the barrel tube 15 during a striping operation.

The barrel bore 17 restricts the initially diverging pattern of the jet stream C of molten spray particles into a narrow, substantially tubular pattern C and discharges these still molten particles in such restricted pattern for deposit onto a suitable surface D toward which the gun B is directed. By moving the gun B with its attachment A along a required path, a stripe 19 of the width of the spray pattern discharged from the barrel tube 15 is deposited on to such surface D;

Referring to the drawings in greater detail, the clamp ring 11), air admitting throat portion 12, and water jacket portion 14, are shown integral, and may consist of a casting or molding of suitable material, such as a ferrous or non-ferrous alloy. The clamp ring portion 19 is of conventional, split ring type, with a usual machine screw 20 for clamping it tightly around the nozzle 11 of a conventional metallizing gun B.

The throat portion 12 comprises four narrow post portions 21, which are integral at one end thereof with the clamp ring portion 10, and at their other ends with the Water jacket portion 14. The latter is tubular, of greater internal diameter than the external diameter of a barrel tube 15 to be used therewith, and is supported co-axially of the clamp ring portion 10. The latter is designed to mount co-axially of the nozzle 11 of a metallizing gun B when the striping attachment A is mounted thereon, as indicated in FIG. 1.

The ends of the water jacket portion 14 are internally threaded, and correspondingly externally threaded gland rings 22 and 23 are screwed, respectively, into these threaded end portions. Each of the gland rings is provided with a radial flange 24 thereon, the flange 24 on the gland ring 22 seating on a sealing gasket 27 on the outer end of the water jacket portion 14, and the flange 24 on the other gland ring 23 seating on a similar sealing gasket 23 on a shoulder 29 formed on inner end of the water jacket portion 14.

A hose fitting 341 is screwed into a threaded hole provided therefor in a boss 31 on one side of the water jacket portion .14, and a second hose fitting 32 is screwed into a similar hole provided therefor in a boss 33 on the other side of the water jacket portion 14. Conventional hoses 34 and 35 are connected to the fittings 3t and 32, respectively, and one of these hoses, for example the hose 34, is adapted to be connected to a suitable supply of water under pressure for providing a flow of cooling water through the water jacket 18 in the space between the Water jacket portion 14 and the barrel tube 15.

A low pressure gauge 37 preferably is provided on the inlet fitting 39, so that when water at adequate pressure to provide the necessary circulation is flowing through the system, a slight pressure reading on this gauge will so indicate. While water is a preferred coolant due to its usual easy availability, the coolant used is not material to the invention, and other coolants, or in fact other cooling means, may be readily substituted for those illustrated and described therein by any routine engineer or designer conversant with the art.

The barrel tube is of suitable material, preferably of high thermal capacity and conductivity, and capable of taking a high polish, such as, for example, copper tubing. The barrel tube is slidably inserted co-axially of the water jacket portion .14 into a pair of conventional O-rings 3S and 39, which are mounted in annular grooves provided therefor, one in each of the gland rings 22 and 23. These O-ihgs effectively position the barrel tube 15 co-axially of, and spaced radially inwardly from, the water jacket portion 14 so as to provide the water jacket 18 in the space therebetween. These O-rings also seal the barrel tube 15 to the water jacket portion 14.

The bore 17 of the barrel tube 15 is highly polished, and preferably is of true, cylindrical shape, since any projection, roughness or irregularity in this surface will cause a rapid build-up of molten spray particles thereon, which requires replacement of the barrel tube.

Replacement of the barrel tube 15 for repolishing or replacement may be easily and quickly accomplished simply by withdrawing the old barrel tube 15 axially from the O-rings 38 and 39, and axially inserting a new one in its place. To avoid damaging the O-rings, and to facilitate the insertion of a replacement barrel axially into the O-rings, the outer edge portion 40 at each end of the barrel tube 15 preferably rounded off, as shown in FIG. 1.

The operation of the illustrative embodiment A of the invention is as follows:

With the striping attachment A secured by means of the clamp ring '10 to the nozzle '11 of a conventional metallizing spray gun B as shown in FIG. 1, so as to position the barrel tube 15 substantially co-axially of the jet stream C from the gun nozzle 11, a supply of cooling fluid, such as water, is fed through the hose 34 and the inlet fitting 30, under sufficient pressure to provide adequate circulation thereof through the water jacket :18. The outlet hose 35 may conduct the water from the water jacket to a suitable point for discharge or recirculation as required. Circulation of the coolant through the water jacket .18 is indicated by a slight pressure reading on the gauge 37.

T he barrel tube 15 is then directed toward the surface D of a suitable work piece 41 to be coated, and is spaced axially therefrom by a required distance of the order of a few inches. The gun B is then actuated to discharge its jet stream of molten particles in the usual fan shaped pattern indicated at C between the nozzle 11 1 and the inlet, or right hand end, of the barrel tube 15 as shown in FIG. 1.

The high velocity flow of this jet stream C of molten spray particles induces a flow of atmospheric air inwardly through the throat openings 13 between the post portions 21, and thence into the barrel tube r15, along with the jet stream C from the gun nozzle 11. Since the principles and nature of such induced or injected air flow are well known, it will be unnecessary to explain or elaborate on them herein.

As the molten spray particles of the jet stream C are carried by this combined air and gas flow into and along the interior of the barrel tube 15, their direction of flow tends to conform to this gas flow, and, due to the restriction of the tubular bore 17 in which they are thus confined, their direction of movement tends to become parallel to the tube axis. Thus, when the spray particles are discharged from the other end of the barrel tube 15 their pattern has become substantially tubular, as indicated at C in FIG. 1. Furthermore, the particle density of this substantially tubular jet stream C as it is discharged from the barrel tube 15 is quite uniform throughout its diameter. When this restricted, substantially tubular pattern jet stream C is moved along a surface D to be coated, as indicated by the arrow 42 in FIG. 1, it forms a stripe 19 of metallizing coating thereon, said stripe having a width substantially equal to the diameter of the jet stream C; at its point of impingement upon the surface D. By employing barrel tubes having bores of different diameters, spray patterns for stripes of different widths can obviously be provided.

The invention provides a simple, inexpensive, striping attachment for metallizing' spray guns, and one which can be easily used by any ordinarily skilled metallizing spray gun operator, practically without instruction. The at tachment applies a full-patterned stripe 19 of metallizing material to a surface D Without the necessity of applying masking material, and later stripping it off. It also conserves the rnetallizing spray material, since the entire restricted spray stream pattern C is directed onto the portion of the surface to be coated.

While I have illustrated and described a preferred em bodiment of the present invention, it will be understood, however, that various changes and modifications may be made in the details thereof without departing from the scope of the invention as set forth in the appended claims.

Having thus described the invention, what I claim as new and desire to protect by Letters Patent is defined in the following claims:

1. A spray pattern restricting striping attachment for a metallizing gun having a discharge nozzle of the type which discharges a jet of molten spray particles co-axially of the nozzle and in a diverging pattern; said attachment comprising (a) a barrel tube support having an opening there through,

(b) means for removably securing the support to such metallizing gun with the opening therethrough centered on the axis of the nozzle of such gun,

(c) a replaceable barrel tube removably mounted in the barrel tube support opening co-axially of the nozzle of a metallizhig gun upon which the support is mounted,

(d) the barrel tube being spaced axially from such nozzle by a distance to receive therein the entire spray jet from such nozzle and to admit therein air from the ambient atmosphere,

(2) the barrel tube being of a diameter substantially smaller than the normal, unrestricted spray pattern from such nozzle at a distance therefrom corerspond ing to the outer end of the barrel tube, thereby to restrict the spray jet from such nozzle to a tubular pattern substantially the diameter of the barrel tube bore, and being (f) of minimum effective length so as to maintain molten spray particles from such nozzle passing there'- through at metallizing temperature.

2.. A spray pattern restricting striping attachment for a metallizing gun having a discharge nozzle of the type which discharges a jet of molten spray particles in a diverging pattern; said attachment comprising:

(a) a tubular water jacket portion,

(b) means for mounting the water jacket portion co axially on a nozzle of such metallizing gun and (c) in axially spaced relation thereto,

(d) a thin walled, replaceable barrel tube removably inserted co-axially Within the water jacket portion, and sealed thereto, said barrel tube being (e) spaced axially from such nozzle when mounted thereon by a distance to admit air from the ambient atmosphere therein and (f) to receive therein the entire spray jet from such nozzle,

(g) said barrel tube being of an internal diameter substantially smaller than the normal, unrestricted 5 spray pattern from such nozzle at a distance therefrom corresponding to the outer end of the barrel tube, thereby to restrict such spray jet to a tubular pattern conforming substantially to the barrel tube bore,

(h) the barrel tube being of minimum effective length to maintain the spray particles passing therethrough at metallizing temperature,

(1) the bore of the barrel tube being of true, cylindrical shape and highly polished so as to minimize adherence thereto of molten spray particles impinging thereagainst, and

(1') means for circulating coolant fluid between the Water jacket portion and the barrel tube for cooling the latter during operation of such gun with the striping attachment so mounted thereon.

3. An arrangement according to claim 2 wherein an annular resilient seal is provided at each end of the water jacket portion and the barrel tube is of an external diameter to fit axially into said seals in sealed relation, and is axially insertable and removable therefirom for easy replacement.

References Cited in the file of this patent UNITED STATES PATENTS 2,747,931 Wilson May 29, 1956 2,861,900 Smith et al. Nov. 25, 1958 3,055,591 Shepard Sept. 25, 1962 

1. A SPRAY PATTERN RESTRICTING STRIPING ATTACHMENT FOR A METALLIZING GUN HAVING A DISCHARGE NOZZLE OF THE TYPE WHICH DISCHARGES A JET OF MOLTEN SPRAY PARTICLES CO-AXIALLY OF THE NOZZLE AND IN A DIVERGING PATTERN; SAID ATTACHMENT COMPRISING (A) A BARREL TUBE SUPPORT HAVING AN OPENING THERETHROUGH, (B) MEANS FOR REMOVABLE SECURING THE SUPPORT TO SUCH METALLIZING GUN WITH THE OPENING THERETHROUGH CENTERED ON THE AXIS OF THE NOZZLE OF SUCH GUN, (C) A REPLACEABLE BARREL TUBE REMOVABLLY MOUNTED IN THE BARREL TUBE SUPPORT OPENING CO-AXIALLY OF THE NOZZLE OF A METALLIZING GUN UPOPN WHICH THE SUPPORT IS MOUNTED, 